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AR# 20484

What is the strength or value of the internal pull-up, pull-down, keeper or bus hold circuit?

Description

What is the strength or value of the internal pull-ups, pull-downs, or keeper (bus hold) circuit in Xilinx I/Os?

Solution

The keeper circuit uses the same pull-up and pull-down resistors that can be enabled separately in the SelectIO block.

The strength of these pull-up/down resistors is typically defined in the "(Xilinx device family) Data Sheet: DC and Switching Characteristics" document, typically as a current strength based on the VCCO voltage level (search for IRPD and IRPU in the device data sheet DC and AC Characteristics).